The term “thermal analysis” denotes here a method in which a sample, which can be of known or unknown composition or constitution, is exposed in a controlled manner to a temperature change, wherein one or more physical variables are measured simultaneously on the sample during this temperature control and are recorded as a temperature-dependent measurement signal.
At least one “measurement curve”, which represents the measurement signal concerned, i.e. a quantitative representation of the physical variable concerned, as a function of the temperature-control temperature, thus results as a direct measurement result of a thermal analysis.
Types of measurements or measurement signals that can be used in thermal analysis are sufficiently known from the prior art, so that this will not be dealt with further. Merely by way of example, the so-called DCS signal (corresponding to the heat flow rate), the mass or change in mass and the length or change in length of the sample may be mentioned as possible measurement signals. Regarding the general prior art of these measurement methods, reference may be made for example to DE 198 25 472 B4, DE 10 2009 038 343 A1 and DE 10 2012 105 101 B3.
The evaluation of results of thermal analyses in the prior art takes place with a relatively low degree of automation. The user usually first has to detect and quantify, using his knowledge and experience, characteristic signal changes in the course of the measurement curve concerned that can be attributed to physical effects. As characteristic effects, signal maxima, signal minima or signal steps can occur in the measurement curve. These effects appearing in the measurement curve, which for the most part originate from conversions (e.g. phase transitions) or reactions of the sample, are often of central interest in the evaluation of the measurement. The prior art in this regard is that a user of evaluation software stipulates that measurement curve points or regions determined by the user himself, such as for example signal maxima, are to be marked and/or that curve integrals are to be calculated in these regions specified by the user.
In a subsequent interpretation of the evaluated measurement curve, the user's experience is again used in that, for example, a measurement curve obtained with a sample of unknown composition is compared with similar measurement curves from the literature or from the user's memory, for which measurement curves an interpretation already exists. The interpretation of the unknown measurement curve then takes place at best through conclusions drawn by analogy.
The evaluation of the measurement result of a thermal analysis practised in the prior art is therefore comparatively complicated, the evaluation results also being influenced to a greater or lesser extent by subjective assumptions and decisions made by the user. In the case of an integration of the thermal analysis as a measurement method in a more complex technical process (e.g. production of goods), the high time consumption on the evaluation of measurement results according to the known methods is also very disadvantageous.